Matrix-mat.



"QTNETED @TATES PATENT @FETfiE.

s Low, 0]? new roan, N. Y., ASSIGNQR 'ro THE o TnEanAr/Ii/mn MFG. 00., 0F

MILWAUKEE, WISCONSIN, A CORPORATION or Wiscons n.

MATRIX-MAT.

No Drawing.

To, all whom z'tmcy concern:

Be it known that I, FRANK S. Low, a citizen of the United States, residing at New York, in the county of NewYork and State of XewYork have invented new and useful Improvements in Matrixfl'ia-ts, of which the following is a full, clear, concise, and exact description.

My invention relates to matrix mats.

These mats are employed in the art of stereotype printing to take an impression of the set. type and thus produce a matrix from which a stereotype plate may be cast.

The practice is to place a uiatupon the set i. type and then apply pressure until the mat receives an impression. This mat then becomes. a matrix from which a stereotype plate may be cast. It is usually required that a stereotype plate be semi-cylindrical in form. The matrix when taken from the type is fiat and in consequence it must be capable of being bent into semi-cylindrical. form when it is placed in the casting machine.

It is manifest that the mat must be capable of receiving an impression and then holding this impression while a stereotype plate is being cast. Often it is required that many plates be cast from the same matrix.

The two. principal mat-swhich-have been developed are wet mats and dry'mats.

WVet mats are made up of sheets of paper which are bound together and impregnated with plastic paste. Starch paste has been employed extensively.

It requires considerable labor and skill to produce a wet mat such as has heretofore been successful. The operator first coats a sheet of paper with the starch paste; thenhe places a second sheet over this paste and covers the second sheet with starch paste, and so on until the sheets have been multiplied to produce a mat of the required thickness. It is required that this mat be kept in a moist condition and not allowed to dry until it is used; otherwise the starch paste will not be sufficiently plastic to produce a successful matrix. It is difficult to keep. a wet mat in proper condition for molding and furthermore delay, trouble and expense are experienced in drying the mat after'it is molded so that a stereotype plate may be cast.

It is obvious that the starch must be sufficiently plastic to readily receive the impres- Specification of Letters Patent.

Patented May 14, 1918.

Application filed June 25, 1914. Serial No. 847,313

destgoy the. impression, or alter the predetermined dimensions of the printed page.

Where there are large. open spaces between the type, bolsters are producedin the mat. If the bolsters are more than a certain size paper pieces must be put back of them so that they will stand up and this involves considerable labor and loss of time.

Anything which contributes to producing a matrix rapidly is important in this art.

et mats have the property of plastic material, and hence actually mold the impression. This gives the best results in the matrix. The surface is smooth and dense and the impression sharp, clear and deep.

The dry mats which have been developed do not really have plastic characteristics. In other words, thcir material does not actually mold in receiving an impression. Thematerial in fact is of such character that if one particle thereof is segregated from'another it will not againintegrallyv re-unite. that actually happens in making an impression is that the mat is embossed or stamped. The character ofthe material is such that a deep impression cannot be obtained. i

If the stereotype. plate sticks to the mat it destroys the matrix. The face of the matrix must be very dense, compact and smooth without any fissures, disruptions or fractures even though they bemerely microscopic, as the molten metal under pressure will creep in to even the slightest crevice or flow around the slightest ledge and cause the natrix to stick. Evenminute fibers lying on the surface or forming the slightest crevices may cause the stereotype plate to stick.

The dry mats have the advantage over the wet mats in that they preserve their propeu ties of taking an impression indefinitely, and hence they may be expeditiously manufaotured in quantities and stored until re quired for use.

Wet mats will give a deep clear impression and be absolutely smooth, but it takes time 7- a long time to dry them, and their plasticity cannotbe preserved without great inconrenience and trouble. Dry mats will remain in an operative condition, but will not allow a deep impression. Cracks. fissures and disruptions are very likely to be produced in making the impression, and moreover, their face is not sufficiently smooth to produce the best results.

The object of the present invention is to produce a mat which will be plastic and which will normally maintain this property indefinitely.

In accordance with this invention, a suit able sheet, as for instance, paper, has incorporated therewith a plastic material which will preserve its plasticity so long as it is subjected to moisture, and to maintain sufficientmoisture there is incorporated with the plastic material a hygroscopic material. The mat thus obtained i'undamentally consists oi fibrous material and hygroscopic plastic material, and these things are combined in such a and are of such character that the matwill not only normally preserve its moldable properties indefinitely, but will withstand the heat to which it must be subjected. h ratrices produced from these mats have strength, flexibility, sharp, clear and deep impressions, smooth and dense sur tacos and are devoid of fissures, ledges or crevices.

One way in which the invention. has so far been carried out will now be explained.

A thick sheet of fibrous absorptive paper is impregnated with a solution of hygro scopic starchy material. This solution must be thin and limpid in order to penetrate the paper. Ordinary unmodified starch will not produce a suiliciently thin and limpid solution. To obtain a solution of the required hygroscopic starchy material, the following method is followed:

pounds ol soluble or modified starch, 2;} pounds of magnesium oxid, and pounds of water, are mixed and then pounds of 70 per cent. acetic acid is added to this mixture. The mixture thus 0 tained is heated to, for instance, 170 F. and pounds otwater are finally added. This smooth and also impervious molten stercvpe metal. The facing may be made up a thinner and liner sneet of fibrous ab; sorptive paper, and one o more sheets of tissue or onion shin paper, the tissue or onion skin paper constituting the face of the mat. These sheets are all pasted one upon another by means ot a starchy paste, which is made up ct three mixtures:

First: pounds cassava starch, l-I gallons oi water;

S econd: pound magnesium oXid, gallon water, g f gallon per cent. acetic acid;

Third: l gallon gum arabic solution made up of 1 pound gum to gallon water.

These three mixtures are combined and heated to 160 or more l Blane line clay whiting or the like may be put into the paste to iacilitate the production of a smooth face.

course various modified starches may be employed in'the impregnating solution,

the purpose being to obtain a starch which will produce a suttlciently thin and limpid solution to impregnate the paper.

This mat may be expeditiously manufao tured by means of a machine in which there is a roll of thick paper, a roll of thin paper, and one or more rolls of tissue paper. The thick paper first passes uarough the impreg nating solution and then the thin paper is pasted thereon. Finally the tissue paper is pasted to the thin paper. lhe web produced is passed through a drier wherein the excess water is removed, and then it is cut into mats of the required size.

Of course the various proportions and the specific materials herein enumerated to set forth an embodiment of invention may be modified in various ways and the process and method of combining them may be varied without departing from my invention.

Having thus described my intention, wnat I claim as new and desire to secure by Letters Patent is,

1. A matrix mat consisting of fibrous material and a hygroscopic plastic material which will not be decomposed by the heat to which it is subjected.

A matrix mat consisting of fibrous material and hygroscopic starchy material which will not be decomposed by the heat to which it is subjected.

3. A matrix mat having sheet of fibrous absorptive paper impregnated with a solu' tion oi hygroscopic plastic material which will not be decomposed by the heat of the molten metal.

A matrix mat having a sheetot fibrous absorptive paper impregnated with a solution of hygroscopic starchy material which will set when moisture is removed therefrom and which will not be decomposed by the heat to which it is subjected.

5. A matrix mat having a sheet of fibrous absorptive paper impregnated with modified starch and hygroscopic material which will not be decomposed by the heat to which it is subjected.

6. A matrix mat having a sheet of fibrous absorptive paper containing starch and hygroscopic material, the hygroscopic ma terial being of such character as will not be decomposed by the heat to which the mat is subjected.

7. A matrix mat having a sheet of fibrous absorptivepaper impregnated with hygroscopic plastic material which will not be decomposed by the heat to which it is subjected and a facing pasted thereon.

8. A matrix mat having a sheet of fibrous absorptive paper impregnated with modified starch containing hygroscopic material which will not be decomposed by the heat to which it is subjected.

9. A matrix mat having a sheet of fibrous absorptive paper impregated with modified starch containing hygroscopic material and a facing fixed thereon by paste made up from ordinary starch and hygroscopic material.

10. A matrix mat having a sheet of fibrous absorptive paper containing modified starch and a hygroscopic material which will not be decomposed by the heat to which it is subjected.

11. A matrix mat havingasheet of fibrous absorptive paper containing modified starch and magnesium acetate.

12. A matrix mat comprising a composite sheet containing hygroscopic plastic material which will not be decomposed by the heat to which it is subjected.

13. A matrix mat comprising a composite sheet containing hygroscopic starch material which will not be decomposed by the heat to which it is subjected.

14. A matrix mat comprising a composite sheet containing modified starch and a hygroscopic material which will not be decomposed by the heat to which it is subjected.

15. A matrix mat comprising a composite sheet containing modified starch and magnesium acetate.

16. A matrix mat having a sheet of fibrous absorptive material impregnated with a solution containing modified starch and magnesium acetate.

17. A matrix mat having a sheet of fibrous absorptive material containing modified starch and magnesium acetate and a facing of tissue paper afiixed thereto by means of a paste containing ordinary starch and magnesium acetate.

18. A matrix mat comprising a sheet of fibrous material impregnated with a modified starch and a compound formed from magnesium oxid and acetic acid.

19. A matrix mat consisting of fibrous material and a hygroscopic plastic material which will not be aifected by the heat to which it is subjected in use.

20. A matrix mat consisting of fibrous material and hygroscopic starchy material which will not be afi'ected by the heat to which it is subjected in use.

In witness whereof, I have hereunto subscribed my name in the presence of two Wit- HBSSGS.

. FRANK S. LOl/V. lVitnesses: V

EDWIN B. H. TOWER, J12, J. E. HUTcHINsoN, Jr.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. 0. 

